ci: ensure the matching poetry version is used (#693)

* We should not be updating dependencies in CI. Hence we should remove
the `poetry update` command
* To install poetry, following the official documentation, we should use
the following command:
https://python-poetry.org/docs/#installing-with-pipx
```shell
pipx install poetry
```

Signed-off-by: Jérôme Benoit <[email protected]>

.github/actions/setup-python-build-env/action.yml

@@ -4,8 +4,7 @@ description: "Install everything needed to build"
 runs:
   using: "composite"
   steps:
-  - name: Upgrage pip and install poetry
+  - name: Install poetry
     shell: bash
     run: |
-      pip install --upgrade pip
-      pip install --user "poetry==1.5.1"
+      pipx install poetry

.github/workflows/publish-to-pypi.yml

@@ -32,7 +32,6 @@ jobs:
       run: |
         proj_version=$(poetry version -s)
         if [ $proj_version != $TAG_VERSION ]; then echo "Version $proj_version, defined in pyproject.toml, does not match TAG $TAG_VERSION of this release"; exit 3; fi
-        poetry update
         poetry publish --build -u __token__ -p $PYPI_TOKEN
       env:
         TAG_VERSION: ${{ steps.context.outputs.TAG_VERSION }}

Makefile

@@ -18,7 +18,7 @@ help:
 	@echo "  release version=<sem. version>   bumps the project version to <sem. version>, using poetry;"
 	@echo "                                   Updates also docs/source/conf.py version;"
 	@echo "                                   If no version is provided, poetry outputs the current project version"
-	@echo "  test                             run all the tests and linting"
+	@echo "  tests                            run all the tests and linting"
 	@echo "  update                           updates the dependencies in poetry.lock"
 	@echo ""
 	@echo "Check the Makefile to know exactly what each target is doing."
@@ -37,7 +37,7 @@ docs: .install-poetry
 	poetry run sphinx-build -b html docs/source docs/build
 
 format: .install-poetry
-	poetry run isort ocpp tests  && poetry run black ocpp tests
+	poetry run isort ocpp tests && poetry run black ocpp tests
 
 tests: .install-poetry
 	poetry run black --check --diff ocpp tests